Straw washer system, device, and method

ABSTRACT

In embodiments, the invention includes a system, an apparatus, and a method for cleaning reusable straws. The system includes a chamber configured to contain a liquid, a siphon to drain the chamber, a transducer to deliver sonic energy to the chamber, and a plurality of straws disposed in the chamber. Each straw includes a tubular wall defining a lumen. The lumen has a length and a cross-sectional area, and the cross-sectional area is substantially constant over the length.

RELATED PATENT APPLICATION

This application is a continuation of U.S. patent application Ser. No. 16/809,517 filed Mar. 4, 2020, entitled Straw washer system, device, and method, which is hereby incorporated by reference.

TECHNICAL FIELD

This invention relates to cleaning of reusable beverage straws.

BACKGROUND ART

Use of disposable beverage straws is a convenient and sanitary way to drink a beverage, particularly when traveling or with a lidded container. However, such straws produce slow-to-degrade plastic waste, as well as packaging waste. Many jurisdictions are restricting the use of disposable straws.

Reusable straws avoid the waste issue but must be cleaned between uses. As straws include long thin hollows, cleaning can be difficult. Conventional dishwashers are generally inadequate to clean reusable straws, particularly when the straws are exposed to viscous or sticky materials. As a result, most users clean reusable straws using an elongated brush or by jetting water directly through the lumen. These labor-intensive methods are particularly unsuitable for high usage location such as restaurants or bars. There is thus a need for a less labor-intensive device and method for cleaning reusable straws.

Reusable straws for personal use may not need to be thoroughly cleaned because the user has already been exposed to his or her own pathogens. In restaurants or bars, straws are reused by other patrons. There is thus a need for a straw cleaning device and method that thoroughly cleans reusable straws.

Reusable straws in a restaurant setting need to be cleaned at a high effective rate. There is thus a need for a device and method for cleaning reusable straws en masse. In a commercial setting, the process requires separate steps of cleaning, rinsing, and sanitizing. There is a need for a device and method that implements the requirements of this commercial process.

DISCLOSURE OF INVENTION/SUMMARY

In embodiments, the invention includes a system, an apparatus, and a method for cleaning reusable straws.

In some embodiments, the invention includes a system including a chamber configured to contain a liquid, a siphon configured to drain the chamber, a transducer configured to deliver sonic energy to the chamber, and a plurality of straws disposed in the chamber. Each straw includes a tubular wall defining a lumen. The lumen has a length and a cross-sectional area, and the cross-sectional area is substantially constant over the length.

The system may include an inlet to add a liquid to the chamber to produce a fill level.

The siphon may include a siphon height. In such embodiments, the siphon may be configured to drain a liquid from the chamber when the fill level exceeds the siphon height.

The system may also include a level sensor and a controller. The level sensor detects when the fill level reaches a predetermined wash height. The controller is operatively connected to the level sensor and to the transducer and is configured to drive the transducer when the level sensor indicates the fill level has attained the predetermined wash height.

In embodiments, the controller is configured to drive the transducer in a frequency range of about 30 to about 50 kilohertz. In other embodiments, the controller is configured to drive the transducer through a swept frequency range of about 39 kilohertz to about 41 kilohertz.

The system may include a wash liquid disposed in the chamber, where the wash liquid includes an aqueous dispersion of a detergent. The wash liquid may include an anionic detergent, a nonionic detergent, a phosphate-free detergent, an enzyme, or a combination of any of these.

In other embodiments, the invention includes an apparatus having a chamber, a basket, an inlet, a drain outlet, a level sensor, a transducer, and a controller. The basket may be removably positionable in the chamber and configured to support a plurality of straws. The inlet may be disposed to add a liquid to the chamber to produce a fill level. The drain outlet may be plumbed to the chamber. The level sensor may be configured to produce a signal when the fill level reaches a predetermined wash height. The transducer may be configured to deliver sonic energy to the chamber. The controller may be operatively coupled to the inlet, to the level sensor, and to the transducer. The controller may be configured to drive the transducer and to alternately raise and lower the fill level.

The drain outlet may include a siphon having a siphon height. The siphon may be configured to drain a liquid from the chamber when the fill level exceeds the siphon height.

The siphon may include a first valve operatively coupled to the controller. The first valve may be configured to disengage the inlet when the first valve is activated. The controller may be configured to activate the first valve when the level sensor produces the signal indicating that the fill level has reached the predetermined wash height.

The controller may be further configured to drive the transducer at a predetermined time after the level sensor produces the signal. The delay of a predetermined time allows for degassing of the liquid.

In some embodiments, the apparatus also includes a dispenser and a reservoir. The dispenser may be plumbed between the chamber and the reservoir so that the dispenser can deliver a fluid from the reservoir to the chamber. The dispenser may be operatively connected to the controller. In embodiments, the chamber may include a heater.

In other embodiments, the invention includes a method of cleaning straws using the apparatus as described above. The method has steps of mounting a plurality of reusable straws into the basket of, of adding a wash liquid to the chamber, and of activating the apparatus.

The wash liquid may contain a phosphate-free detergent. In embodiments, the wash liquid may include an anionic detergent, a nonionic detergent, an enzyme, or a combination of these. The step of adding a wash liquid may include loading a prepackaged concentrate to the chamber and adding water to the chamber.

The step of activating the apparatus may include causing the controller to perform the steps of ultrasonicating the wash liquid and of draining the chamber. The activating step may further include causing the controller to sanitize the chamber and the straws. This sanitizing step may include heating the chamber contents, filling the chamber with a liquid containing a sanitizing agent, or a combination of these.

The activating step may further include causing the controller to degas the wash liquid.

The step of activating the apparatus may also include a plurality of substeps of draining and filling the chamber. The drain outlet may have a siphon including a siphon height. The substeps of draining and filling the chamber may include adding a liquid via the inlet and draining the liquid when the fill level of the chamber exceeds the siphon height.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a first perspective view of an embodiment of the system of the invention including the apparatus of the invention.

FIG. 1B shows a second perspective view of the embodiment of FIG. 1A.

FIG. 1C shows a partial sectional side view of the embodiment of FIG. 1A through a plane along the midline of the siphon to show internal structure.

FIG. 2 shows a perspective view of an embodiment of the apparatus with the basket removed.

FIG. 3 shows a perspective view of a basket to fit with the apparatus of FIG. 2.

FIG. 4 shows a perspective view of the basket of FIG. 3 partially packed with straws.

FIG. 5 shows a perspective view the basket of FIG. 2 shown partially inserted into the apparatus of FIG. 2.

FIG. 6 shows a block diagram of active components of embodiments of the invention.

FIG. 7 shows a detail of an embodiment of the keypad of FIG. 2.

FIG. 8 shows steps of a method of the invention.

FIG. 9 shows a rear perspective view of another embodiment of the device of the invention.

DETAILED DESCRIPTION

The invention includes an apparatus, a system, and a method.

An embodiment of the system of the invention is illustrated in FIGS. 1A-1C. System 1 includes a chamber 100, a basket 300 configured to hold one or more straws and to support the straws within the chamber 100, and a plurality of straws 30 disposed in basket 300.

Each of prior art straws 30 includes a tubular wall, generally though not exclusively cylindrical, that defines a lumen. The lumen has a length, a diameter, and a cross-sectional area. The length of each straw is large with respect to its diameter. Typical ranges are about 0.1 to 0.4 inches (2.5-10 mm) for the diameter and 4 to 10 inches (100-250 mm) in length. Straws 30 have cross-sectional area substantially constant over the length. This is important because system 1 relies upon a combination of ultrasonication and repeated filling and draining. I have found that the efficacy of washing depends upon the frequency of ultrasonication. A frequency range of about 30 to about 50 kilohertz provides good coupling to most common straw dimensions. A swept frequency of about 39 to about 41 kilohertz, when combined with subsequent filling and draining steps, is adequate to insure reliable cleaning. However, this is true only if the straws have relatively constant cross-sectional area over their length. When cross sectional area changes over the length (as in a pipette or eyedropper) much of the ultrasonic energy is reflected and does not effectively contribute to cleaning.

Chamber 100 is the location where the cleaning process takes place. Chamber 100 is a hollow vessel, which may be open at the top for easy insertion and removal of basket 300. In other embodiments, chamber 100 may have a lid. In operation chamber 100 accepts a plurality of straws 30, which are then submerged in one or more wash liquids. In some commercial implementations, US FDA and other regulations require a three-phase wash. The wash liquids have different names in the different phases. The wash liquid during a cleaning phase is a cleaning liquid. The wash liquid during a rinse phase is a rinse liquid. The wash liquid during a sanitizing phase is a sanitizing liquid. These liquids may all be the same liquid based on regulatory requirements. Generally, the liquids may include different materials: wash liquids may include detergents; rinse liquids may be pure water; sanitizing liquids may include sanitizers.

Chamber 100 may accommodate liquids at different temperatures. In some embodiments, these different temperatures may be attained by mixing hotter and colder streams from external hot and cold-water lines. In other embodiments, chamber 100 includes a fluid heater 250 and temperature sensor 252 to regulate wash liquid temperature. Chamber 100 may include a second temperature sensor proximal to temperature-sensitive parts, such as transducers 150. The second temperature sensor monitors the temperature proximal to transducers 150 to assure that these components remain at a safe temperature.

During the cleaning phase of the wash process, chamber 100 delivers ultrasonic energy to the cleaning liquid and to straws 30. The cleaning liquid may be heated or maintained between ambient temperature and about 120 F. After ultrasonication, chamber 100 may be drained, and then repeatedly filled and drained in a rinse phase to rinse straws 30 and chamber 100 of any waste materials. Rinse liquid may also be heated.

After the rinse phase, chamber 100 enters a sanitizing phase. The sanitizing phase may include filling the chamber above the top of the straws (such as predetermined level 189) with a sanitizing liquid. A sanitizing liquid may be water that is heated to at least about 171 F. Alternatively, the sanitizing liquid may include a sanitizing agent dispersed in water. Sanitizing agents include hypochlorite bleach or chemicals having antibacterial action. Depending on the sanitizing liquid and other requirements, the sanitizing liquid may be heated to between about 75 F and about 171 F for a minimum of thirty seconds.

Chamber 100 includes a chamber wall 110, an inlet 172, an outlet, and one or more ultrasonic transducers 150. Chamber wall 110 forms a fluid tight vessel, which is roughly cylindrical in the illustrated embodiments. Other shapes are possible, but the cylindrical shape allows for fairly compact packing of straws 30.

Inlet 172 supplies wash liquid to chamber 100. In embodiments, inlet 172 is a plumbed connection to a water line. In some embodiments, inlet 172 includes an integral fill valve 174 that opens and closes under program control. Fill valve 174 (and other valves, if present) generally require higher currents than may be supplied by controller 200. As visible in FIG. 6, apparatus 10 includes valve driver 260 to supply the necessary drive signals to fill valve 174 and any other valves under the control of controller 200.

Inlet 172 is shown with fill valve 174 that (under program control by controller 200) allows or blocks flow of water or other wash fluid into chamber 100. This advantageously reduces external electrical or control interfaces. FIG. 1C shows fill valve 174 in the closed position blocking flow through inlet 172. However, it is expressly within the scope of the invention that the filling process may be mediated by an external valve not part of apparatus 10. Such an external valve may operate under program control by controller 200 or may be independent of apparatus 10. In some embodiments, a user simply turns on a water source external to apparatus 10 at appropriate points in the wash process.

The purpose of the outlet is to drain expended wash liquids from chamber 100. The outlet is shown in the illustrated embodiments as siphon 170 that drains chamber 100 once the fill level is sufficient. This advantageously reduces the cost and complexity of apparatus 10. However, it is expressly within the scope of the invention that the outlet may additionally or alternatively include a drain valve 178 or a pump (not illustrated) to drain or assist in draining chamber 100. Drain valve 178 may be placed anywhere in siphon 170 or alternatively, siphon 170 may be replaced by a simple conduit connected to the bottom of chamber 100 with drain valve 178 positioned to interrupt flow through that conduit. Driving force for draining may be pump-assisted or may rely on gravity.

As illustrated, siphon 170 includes chamber drain 180 connected at or near the bottom of chamber 100. Chamber drain 180 then fluidly connects to siphon up tube 184 that runs upward along the side of chamber 100. Siphon up tube 184 fluidly connects at its upper end to siphon conduit 186. Siphon conduit 186 then fluidly connects to siphon down tube 182 that runs downward along the side of chamber 100 parallel to siphon up tube 184. The end of siphon down tube fluidly connects to an external sink or drain that must be below the level of the bottom of chamber 100.

Chamber drain 180, siphon up tube 184, siphon conduit 186, and siphon down tube 182 together form siphon 170 that has siphon drain level 190 at about the height of siphon conduit 186. In operation, if liquid is added to chamber 100 (such as through inlet 172), chamber 100 fills until the level of liquid in chamber 100 reaches siphon drain level 190. Since siphon up tube 184 has a fluid connection through chamber drain 180 near the bottom of chamber 100, the level of liquid in siphon up tube 184 rises roughly together with the level of liquid in chamber 100. Once the level of liquid in siphon up tube 184 reaches siphon drain level 190, liquid spills through siphon conduit 186 into siphon down tube 182 and falls down siphon down tube 182. If siphon down tube 182 has cross section in appropriate proportion to that of siphon up tube 184, the liquid will fill the cross section of siphon down tube 182 and create a “suction” that draws liquid out of chamber 100 until the liquid level of chamber 100 falls below the top of chamber drain 180. This familiar siphon action drains chamber 100 based on fill level alone, without the use of active components (such as valves or pumps) in siphon 170.

I have found that when siphon up tube 184 has area at least about twice that of siphon down tube 182 a siphoning effect may be consistently established. A ratio of about 2.25 between these areas provides a good match to standard pipe sizes. In an apparatus designed to accommodate up to 700 straws, siphon down tube 182 may have a diameter of about 1 inch and siphon up tube 184 may have a diameter of about 1.5 inch.

Ultrasonic transducers 150 may be piezoelectric devices well known in the art. These are typically driven by a relatively high voltage-low current driver at a desired range of frequencies. As visible in FIG. 6, apparatus 10 includes a transducer driver 220 that supplies the necessary drive signals to transducers 150 under the control of controller 200. Such driver circuits are well known in the art. Controller 200 is electrically connected to transducer driver 220 and transducer driver 220 is electrically connected to each of transducers 150.

The intensity of sonication may be sufficient to induce cavitation in the wash liquid. This may produce very high local pressures in chamber 100. For this reason, apparatus 10 is designed to be used with straws that do not break easily; glass straws are not suitable. In embodiments, the system of the invention includes straws that are limited to materials other than glass.

Ultrasonic transducers are generally not compatible with wet conditions; these may be mounted on an external surface of chamber 100. In the illustrated embodiment, chamber 100 includes a subfloor 140 that forms a liquid tight seal with the chamber wall 110. One or more of transducers 150 are bonded to the lower surface of subfloor and couple ultrasonic energy through subfloor to the contents of chamber 100. The use of subfloor 140 advantageously keeps the transducers 150 and their drive voltages isolated from both the contents of chamber 100 and from environmental hazards.

To effectively deliver ultrasonic energy to straws, chamber 100 is filled with wash liquid as a coupling medium. Since wash liquid supplied by a plumbed line may be aerated, it may be useful to let the wash liquid stand for a time to degas. Both of these steps require that chamber 100 be filled with wash liquid but not drained. In embodiments, chamber 100 includes level sensor 240 that detects when the liquid fill level of chamber 100 is sufficient to submerge straws 30 but not so high as to cause draining through siphon 170.

Level sensor 240 may be placed on chamber wall 110 at predetermined level 189. Importantly, predetermined level 189 is lower than siphon drain level 190. Level sensor 240 may be any of a number of conventional liquid level sensors that give an electrical signal once the predetermined level is reached. Possible examples include as a capacitive sensor, an optical sensor, a float valve, a load cell, or a similar device.

Level sensor 240 is electrically connected to controller 200 so that controller 200 may sense when the fill level reaches predetermined level 189. In normal operation, controller 200 opens fill valve 174 to fill chamber 200 and closes fill valve 174 when level sensor 240 signals that predetermined level 189 has been reached. Controller 200 may include a monitor routine that closes fill valve 174 after a sufficient time to fill under normal circumstances even if level sensor 240 does not signal. This helps prevent floods in the event of device failures. Additional safety features include shutoff 280. Shutoff 280 mechanically closes siphon 170 to prevent flooding. This may be a manual closure or may be mediated by controller 200. In some embodiments, shutoff 280 closes both siphon 170 and fill valve 174.

In some embodiments, device 10 includes a fluid heater 250. Fluid heater 250 operates together with one or more temperature sensors 252 and thermal driver 258 to heat wash liquids. Temperature sensor 252 measures the temperature of wash fluids and communicates the measured temperature to controller 200. Controller 200 compares the measured temperature with the set temperature, which may vary during the phases of the wash cycle. Controller 200 uses a temperature control algorithm, such as a PID control algorithm, and commands thermal driver 258 to apply an appropriate heating current to fluid heater 250. The temperature control algorithm may be modified by a requirement to keep temperature-sensitive parts such as transducers 150 within a safe envelope. This may be accomplished by monitoring the temperature near transducers 150 and slowing the rate of temperature increase if the temperature near transducers 150 approaches an unsafe temperature. In some embodiments, a mixer such as a rotating blade (not shown) may be disposed in chamber 100 to help distribute heat more evenly.

In other embodiments, device 10 includes one or more temperature sensors 252, a mixing valve 254 plumbed to sources of hot and cold water, and a mixing valve driver 256. Temperature sensor 252 measures the temperature of wash fluids and communicates the measured temperature to controller 200. Controller 200 compares the measured temperature with the set temperature, which may vary during the phases of the wash cycle. Controller 200 uses a temperature control algorithm, such as a PID control algorithm, and commands mixing valve driver 256 to adjust the relative proportions of hot and cold water from mixing valve 254. Embodiments of this type may also include heaters and thermal controllers to maintain the set temperature.

In other embodiments, wash liquids are not heated.

Controller 200 may be an electrical controller such as a microprocessor, a microcomputer, a gate array, or similar device known in the art. In embodiments, controller 200 may be a single-chip microcontroller such as the PIC 18F25K83 manufactured by Microchip Technology Inc. of Chandler, Ariz. or a board-level microcontroller such as a Raspberry Pi 4 single board computer developed by the Raspberry Pi Foundation of the United Kingdom, or the Arduino MKR WiFi 1010 developed by U-BLOX of Thalwil, Switzerland. Controller 200 is programmed to execute a sequence of steps that operate system 1. The programming of electronic devices such as controller 200 is well known in the art. Controller 200 may also include interface electronics for communicating (either directly or wirelessly) with other devices, such as a remote cellular phone or site automation system coordinating multiple tasks in an environment such as a home or restaurant.

Controller 200 may also optionally include indicators such as visible LEDs or a display, real time clock functionality to define the timing of events, and memory storage to record usage and errors. In embodiments, controller 200 controls the operation of the various parts. The description of this document refers to operations performed by the system or by a component of the system or apparatus. These references refer to control by controller 200 as mediated by appropriate drivers and by software known in the art.

Basket 300 is sized to hold a plurality of straws 30 in an upright position. Basket 300 includes a handle 330, a base 310, and side 320. In some embodiments, basket 300 forms a fluid permeable cylinder that fits within chamber 100 with sufficient clearance to permit easy positioning and removal. Basket 300 may be formed largely of mesh or perforated material to allow wash liquids to freely bathe straws 30. Suitable materials for basket 300 include stainless steel or other corrosion-resistant metals and high strength polymers. Base 310 may include a perforated sheet as in illustrated in FIG. 3. Alternatively base 310 may be formed of a wire mesh.

In embodiments, handle 330 includes paired handle uprights 332 separated by the diameter of basket side 320. Handle uprights 332 connect to basket side 320 and are themselves connected by top piece 340 above side 320. Top piece 340 forms a convenient gripping surface to insert and remove basket 300 from chamber 100.

Basket 300 also includes features to support basket 300 within chamber 100. In the illustrated embodiment, handle 330 includes a pair of supports 334 that are extend outwardly from handle uprights 332 on two sides. Supports 334 fit within complementary hollows in chamber wall 110 and upon support rims 130 at the lower surface of these hollows. When basket 300 is lowered into chamber 100 with handle uprights 332 aligned with the hollows, supports 334 rest upon support rims 130 holding basket 300 in operative position to clean straws 30. Other embodiments of support features will be apparent to those skilled in the art. For example, basket 300 may include raised feet depending from base 300. Such feet may also aid in draining of straws 300 after washing is complete.

Basket 300 may include internal partitions (not shown) to hold straws 30 upright when less than a full load of straws is in basket 300. In some embodiments, the internal partitions may be removable so that, when basket 300 is partially filled with straws 30 to be cleaned, an internal partition may be inserted to support the less than full load. Such internal partitions may be formed of porous compliant material that flexes to hold the straws against basket walls.

Basket 300 may also be subdivided to support less than a full load of straws 30. Such subdivisions (not shown) may each accommodate a plurality of straws 30 (such as by quartering basket 300 into sectors) or may accommodate individual straws.

Device 10 may include a housing 20 to protect internal portions of the apparatus and to provide a more pleasing appearance. Housing may cover active electronic components as illustrated in FIG. 6. Other support components, such as a power supply (not shown) may also be placed within housing 20. Chamber 100 may be encased in outer wall 120 to cover internal components and to provide insulation. In some embodiments, fluid heater 250 may include one or more thin film heaters wrapped around the outer aspect of chamber wall 110. Alternatively or additionally a fluid heater 250 may be disposed about inlet 172 or in chamber 100 beneath basket 300.

Device 10 may also include one or more reservoirs 510 and associated fill ports 520 and dispensers 530. Each reservoir holds a relatively large volume (sufficient for multiple wash cycles) of a liquid cleaning concentrate or sanitizing concentrate. Each reservoir includes a fill port 520 to allow refilling of reservoir 510.

Each reservoir 510 is plumbed via its associated dispenser 530 to chamber 100. Dispenser 530 may be one of many pump types known in the art, such as a solenoid pump that transfers fluid through when the solenoid is energized. Exemplary pumps include the MONO series of solenoid pumps manufactured by Fluid-o-Tech S.R.L. of Milan, Italy. Such solenoid pumps may deliver an appropriate volume of concentrate by controlling the length of time the pump is activated. These pumps may be operated by controller 200 together with a dispenser driver 230 to adjust voltages and currents. Dispenser 530 may be further separated from chamber 100 by a check valve to prevent unintended flow in the event of power loss.

In embodiments, each reservoir 510 may include reservoir sensor 512 that senses the fill level of reservoir 510. Before each wash cycle, controller 200 may interrogate reservoir sensor 512 to determine whether sufficient concentrate is present in reservoir 510. If the amount is lower than a predetermined amount, controller 200 may set an indicator to signal that refill or reservoir 510 is needed.

Housing 20 may also support keypad 160. Keypad 160 allows a user to simply operate apparatus 10. As illustrated in FIG. 7, keypad 160 may include one or more switches and one or more indicators. These may be combined in an interactive touchscreen or may be remotely operated through an external communication link. In some embodiments the keypad may be replaced or augmented by a remote device such as an application in a cellular phone or tablet.

As illustrated, keypad 160 includes first switch 162 marked DEGAS, second switch 164 marked RUN, first indicator 166 marked READY, and second indicator 168 marked RUN. These switches and indicators may be connected to controller 200 to control operation and indicate status of apparatus 10.

In embodiments, the invention includes a cleaning solution and a cleaning solution concentrate. The cleaning solution concentrate is a more easily shippable and storable form of the cleaning solution, formulated to be combined with water.

In embodiments, the cleaning concentrate may be packaged in a unit dose form. One unit dose package contains a quantity of cleaning solution concentrate that, when mixed with water, is appropriate to clean a full load of straws in the apparatus of the invention. There may be more than one size of unit dose package to complement different size apparatus. In embodiments, a unit dose of cleaning solution concentrate may be packaged in a capsule that dissolves or opens when exposed to water or to ultrasonic energy during the cleaning process.

In some embodiments, the components of the cleaning concentrate include a mixture of powders, granular solids, or liquids. In embodiments, the cleaning concentrate may include non-phosphate liquid detergents such as Chem-Crest® 211 manufactured by Crest Ultrasonics Corporation of Ewing, N.J. In other embodiments, the cleaning concentrate may include the anionic detergent Alconox® or the anionic detergent with protease enzyme Tergazyme®, both manufactured by Alconox, Inc. of White Plains, N.Y. Each of these product names is a registered trademark of its manufacturer.

In embodiments, the invention sanitizes straws by heating a sanitizing liquid that surrounds them. The sanitizing liquid may be water that is heated to at least about 171 F.

In other embodiments, the invention sanitizes straws by exposing the straws to a sanitizing liquid that includes a dispersed sanitizing concentrate. The sanitizing concentrate is a more easily shippable and storable form of the sanitizing agent, formulated to be combined with water.

In embodiments, the sanitizing concentrate may be packaged in a unit dose form. One unit dose package contains a quantity of sanitizing solution concentrate that, when mixed with water, is appropriate to sanitize a full load of straws in the apparatus of the invention. There may be more than one size of unit dose package to complement different size apparatus. In embodiments, a unit dose of cleaning solution concentrate may be packaged in a capsule that dissolves or opens when exposed to water or to elevated temperature during the sanitizing process.

In some embodiments, the sanitizing concentrate includes an alkyl ammonium chloride mixture such as Bacti-Free Third Sink Sanitizer distributed by Noble Chemical of Lancaster, Pa.

In embodiments, unit dose quantities of cleaning concentrate and sanitizing concentrate in separate compartments of a combined unit dose pack. The separate compartments are designed to be released at the appropriate phase of the cycle.

In some embodiments, either or both concentrates may be loaded into respective reservoirs 510 in device 10. Dispensers 530 transfer a predetermined amount of the respective concentrate from its associated reservoir 510 under control of controller 200. Exemplary dispensers include a dispensing pump. Dispensing pumps may be of many types known in the art, including the MONO series of solenoid pumps manufactured by Fluid-o-Tech S.R.L. of Milan, Italy. These pumps may be operated by controller 200 together with a pump driver to adjust voltages and currents.

FIG. 9 illustrates an embodiment including two reservoirs 510 (for example, dedicated respectively to a cleaning concentrate and a sanitizing concentrate). Each reservoir 510 includes a fill port 520 (covered in the figure by a screw top lid) and a dispenser 530. Each dispenser 530 is plumbed through chamber wall 110 to chamber 100 at a position near the bottom of chamber 100. The embodiment of FIG. 9 may be otherwise similar to the embodiment of FIG. 2. Each dispenser 530 is electrically connected to dispenser driver 230, which is electrically connected to controller 200. In operation, controller 200 commands a dispenser to add an aliquot of a concentrate during the respective phase.

The invention also includes a method 400 of cleaning one or more straws using embodiments of the apparatus as described above. The method includes steps of loading straws into a basket (410); adding a wash concentrate to the chamber (420); adding a wash liquid to the chamber (430); and activating the apparatus (440).

After activating the apparatus, in some embodiments, controller 200 directs further steps under program control. These steps include degassing the wash liquid (442), ultrasonicating the chamber contents (444), sanitizing the chamber contents (446), and performing a sequence of draining and filling steps (448) to rinse the straws and chamber. A final step may include draining without refilling.

In some embodiments, the READY indicator indicates the device is ready for use. A user may pack the dirty straws into basket 300 and place basket 300 into chamber 100. User then adds wash concentrate to chamber 100 and presses first switch 162 to begin the cleaning process. Controller 200 senses the keypress and opens fill valve 174 to begin to fill chamber 100, resets the READY indicator, and sets the RUN indicator. In other embodiments, controller 200 causes a dispenser 530 to transfer a predetermined quantity of cleaning concentrate to enter chamber 100. Once controller 200 receives a signal from level sensor 240 that the fill level has reached predetermined height 189, controller 200 closes fill valve 174 and waits a predetermined period for the cleaning liquid to degas, and, in some embodiments, preheat by activating fluid heater 250 driven by thermal driver 258. In other embodiments, controller 200 in combination with mixing valve driver 256 and mixing valve 254 may additionally or alternatively adjust the temperature. During this period the cleaning concentrate disperses in the liquid to form the cleaning liquid.

After a degas and heating interval of about five to about 15 minutes, the controller begins ultrasonication by sweeping in a frequency range of about 39 to about 41 kilohertz. After about 15 minutes of sonication, the controller stops sonication and opens fill valve 174. The controller holds fill valve 174 open for sufficient time to fill and drain chamber 100 a predetermined number of times.

In some embodiments, controller 200 begins a sanitizing phase by monitoring level sensor 240 and closing fill valve 174 when the fill level reaches predetermined level 189. Controller 200 then causes a second dispenser 530 to transfer a predetermined quantity of sanitizing concentrate to enter chamber 100 and may again heat the contents of chamber 100 as described above. Following the sanitizing phase, controller 200 opens fill valve 174 to cause chamber 100 to drain by exceeding siphon drain level 190.

In some embodiments, controller 200 may time the interval between repeated detection of signal changes from level sensor 240 as chamber 100 fills and drains. Controller 200 may calculate how long to hold fill valve 174 open based on this timing so that chamber 100 ends the wash process empty. This length of time is expected to vary based on water pressure and on the number of straws 30 in basket 300.

In other embodiments, the DEGAS step may precede loading of straws into chamber 100. In these embodiments, user first presses the DEGAS switch and waits for controller 200 to set the READY indicator after the degas step is complete. User then loads the straws and presses the RUN switch to continue the cycle.

The embodiments described herein are referred in the specification as “one embodiment,” “an embodiment,” “an example embodiment,” etc. These references indicate that the embodiment(s) described can include a particular feature, structure, or characteristic, but every embodiment does not necessarily include every described feature, structure, or characteristic. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, such feature, structure, or characteristic may also be used in connection with other embodiments whether or not explicitly described.

Further, where specific examples are given, the skilled practitioner may understand the particular examples as providing particular benefits such that the invention as illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein or within that particular example.

This disclosure may mention certain other documents incorporated by reference. Where such documents conflict with the express disclosure of this document, this document shall control.

It will be apparent to those of ordinary skill in the art that many modifications and variations of the described embodiment are possible in the light of the above teachings without departing from the principles and concepts of the disclosure as set forth in the claims.

Although the present disclosure describes certain exemplary embodiments, it is to be understood that such disclosure is purely illustrative and is not to be interpreted as limiting. Consequently, without departing from the spirit and scope of the disclosure, various alterations, modifications, and/or alternative applications of the disclosure will, no doubt, be suggested to those skilled in the art after having read the preceding disclosure. Accordingly, it is intended that the following claims be interpreted as encompassing all alterations, modifications, or alternative applications as fall within the true spirit and scope of the disclosure. 

I claim:
 1. A method of cleaning straws comprising: providing an apparatus having: a chamber; a basket removably positionable in the chamber and configured to support a plurality of straws; and a transducer configured to deliver sonic energy to the chamber; loading a plurality of straws into the basket; positioning the basket in the chamber; adding a wash liquid to the chamber; ultrasonicating the wash liquid; sanitizing the plurality of straws; rinsing the chamber; and emptying the chamber.
 2. The method of claim 1, wherein the wash liquid includes a phosphate-free detergent.
 3. The method of claim 1, wherein the step of adding a wash liquid includes loading a prepackaged concentrate to the chamber and adding water to the chamber.
 4. The method of claim 1, wherein the apparatus further includes a heater configured to heat chamber contents, and wherein the step of sanitizing the plurality of straws includes heating the chamber contents.
 5. The method of claim 4, wherein the apparatus further includes a temperature sensor configured to sense a temperature of the chamber.
 6. The method of claim 5, wherein the step of sanitizing the plurality of straws includes heating the chamber to a temperature of at least 171 F.
 7. The method of claim 6, wherein the apparatus further includes a controller operatively connected to the heater and to the temperature sensor, the controller configured to control the chamber temperature, wherein the step of sanitizing the plurality of straws includes maintaining the temperature of at least 171 F for at least thirty seconds.
 8. The method of claim 7, wherein the apparatus further includes a level sensor operatively coupled to the controller, the level sensor configured to detect a liquid in the chamber at a predetermined height, and wherein the step of adding a wash liquid comprises adding the wash liquid until the wash liquid reaches the preset height.
 9. The method of claim 8, wherein the step of rinsing the plurality of straws includes one or more steps of draining and refilling the chamber.
 10. The method of claim 9, wherein the apparatus further includes a siphon plumbed to the chamber, the siphon having a siphon height, and a fill valve operatively coupled to the controller and configured to add a liquid to the chamber, and wherein the step of draining and refilling the chamber includes opening the fill valve and draining the liquid when the fill level of the chamber exceeds the siphon height.
 11. The method of claim 10, wherein the preset height is below the siphon height.
 12. The method of claim 11, wherein the step of emptying the chamber comprises draining any liquid remaining in the chamber.
 13. The method of claim 12, wherein the step of draining any liquid remaining in the chamber includes the controller determining a siphon time from the step of draining and refilling the chamber, and opening the fill valve for a drain time calculated from the siphon time.
 14. The method of claim 1, wherein the step of adding a wash liquid to the chamber includes holding the wash liquid in the chamber for a degas time.
 15. The method of claim 14, wherein the degas time ranges from about five to about fifteen minutes.
 16. The method of claim 1, wherein the apparatus further comprises a dispenser and a reservoir, the reservoir containing a wash concentrate, the dispenser plumbed between the reservoir and the chamber, the dispenser operatively connected to the controller, and wherein the step of adding a wash liquid includes transferring an aliquot of the wash concentrate from the reservoir to the chamber.
 17. The method of claim 16, wherein the apparatus further comprises a reservoir sensor operatively connected to the controller, the reservoir sensor configured to sense a fill level of the reservoir, wherein the controller indicates a need to refill the reservoir when the reservoir sensor senses that the fill level of the reservoir is less than a predetermined amount. 